Multiple-voltage system of motor control.



E. W CHENEY. MULTIPLE VOLTAGE SYSTEM OF MOTOR CONTROL. APPLICATION FILED 00T. s w09.

960,505. Ptented June 7,1910. v I ZSKEETB-EHEET 1.

H. W. CHENEY. MULTIPLE VOLTAGE SYSTEM 0F MOTOR CONTROL. APPLIGATION FILED 0011.6, 1909.

2 SHEETS-SHEET 2.

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Patented .111115731910 improve the arrangement shown 'UNITED STATE@ HERBERT W. CHENEY, OF MILWAUKEE, VJISCNSIN, ASSIGNOR T0 ALLSCHALMERS COMPANY,\A CGRPOR-A'EION OF NEW JERSEY.

hIULTIPLE-VOLTA-GE SYSTEM DE MOTGR CONTROL.

Specification of Letters Patent.

Fat-criteri June *7, 1%10.

Application filed october G, i902). Serial 521,371.

yresistance is temporarily cut into the armature circuit of a motor whenever the connections of the armature are changed :trom one set of mains to another. rlhis resistance, now commonly known as a buer resistance, serves toprevent excessive surges of current through the armature when the impressed voltage thereon is either increased o r decreased. This buder resistance, after having been inserted in circuit is cut out again after a predetermined time, which, in the Dunn patent, is controlled by an ordinary air dash -,pot. -While this arrangement is generally entirely sufficient, it sometimes happens that the buffer resistance is cut out too quickly or too slowly, largely on account of imperfections in the dash-pot and of its direct connection to the switching device controlling the buffer resistance. The action has been improved somewhat by substitilting` an ordinary oil daslrpot for the air dash-pot described by Dunn, but because of the stuffing boxes and other features of the' oil dash-pot and the aforesaid direct corncction there are drawbacks to its use also.

It is the object of my present invention to the Dunn patent, particularly as regs the means for controlling the cutting out of the butler resistance.

In carrying out my invention there is provided means f'or normally preventing` the cutting out of the buffer resistance after it has been cut in, and an.electro-magnetically operated device for rendering the aforos id means inoperative. The elcctro-n'iagnetic device preferably operates only after a time interval after the cutting` in of the butler resistance, thc time interval being` obtained in the preferred form of' my invention by a dasli-pot of special construction. rlhe piston of this daslrpot is part of the magnetic circuit or the Ielectro-magnetic device and is so arranged that there is no need of stuliing boxes, although the dash-pot may operate in oil. v

rlhe various novel features of my invention will appear from the description and drawings, and will be particularly pointed out in the claims.

Figure l is a section through a controller embodying' my invention, showing the operating` mechanism for the buffer resistance switch; Fig. 2.is an enlarged viewof the electro-magnetic time element device; Fig'. 3 is a partial front elevation of the controller of Fig.. l, with some parts broken away ff.

and Fig. el is a diagram showing` a development of the controller.

F or the salie of simplicity, the controller is here illustrated with its connections approximately the same as those in the patent to Dunn, aforesaid, but it is obvious that my invention is applicable to any other form of controller in which the voltage impressed on 'a motor is varied and especially applicable to any form of multiple voltage controller'. rlhe controller drum 3l is operable by the usual handleBQ, and has contact segments 33 arranged to cooperate with contact fingers 34 to 39 inclusive to connect the armature of a motor M to different sets vof the mains c, Z), c, and al. The drum also has a ring i0 and segments el' arranged to cooperate with contact fingers 42 and 4S inclusive to vary the resistance 7' in the field circuit of the motor M.

Mounted on the shaft of the controller is a cam wheel 49, on the periphery of which rides a. roller 50 carried by alever 5l. The A cam wheel llt) is shown developed in Fig. 2, but in order to show more clearly the operation of the device it is there shown as if its cam projections were on its upper' surface instead of on its periphery. These cani projections are so located that they engage with and move the roller 5() as the motor armature connections are being* changed accesos 'switch as the motor armature connections are changed from one Set of mains to another, a latch for holding said 'switch open, and electro-magnetic means for releasing said latch.

5. In combination, a controller arranged to connect a motor armature to ldifferent sets of multiple voltage mains, a resistance, a switch arranged to be operated to cut said resistance into the motor armature circuit when the armature connections are changed from one set of multiple voltage mains to another, a latch for holding said switch in the position in which said resistance is in circuit, and electro-magnetically operated means for releasing said latch.

G. In combination, a controller arranged to connect a motor armature to different sets of multiple voltage mains, a resistance, a switch arranged to be operated to cnt said resistance into the motor armature circuit when the armature .connections are changed from one set of multiple voltage mains to another, a latch for holding' said switch in the position in which the said resistance is in circuit, and electromagnetic means for re leasing said latch, said electromagnetic means being energized when said resistance isv cnt into the motor armature circuit.

7. In combination, a controller arranged to connect a motor armature to different sets ot.' multiple voltage mains, a resistance for the motor armature circuit, a switch normally short-circniting said resistance, means for opening-said switch by a movement of the controller to change the motor armature connections from .one set ot multiple Voltage mains to another, a latch for "iolding said switch open, and electro-magneticalljyY open ated means for releasing said latch.

8. l'n combination, a controller arranged to connect a motor armature to dill'erent sets ot multiple voltage mains, a resistancev ttor the motor armature circuit, a switch normally short-circuitinf; said resistance, means :for opening said switch by a movement ot the controller to change the motor armature connections l'rom one set oit multiple voltage mains to another, a latch for holding said switch open, and electro-magnetic means for releasingF said latch, said electro-magnetic means being` energized by the opening, of said switch.

9. ln combination, a controller arranged to connect a motor armature to different sets ot multiple voltage mains, a resistance for the motor armature circuit, a switch which normally short -circnits said resistance, means for opening' said switch hy a movement of the controller to change the motor armature connections 'trom one set ol multiple voltage mains to another, and electromagnetic means energized upon the opcnintr ot' said switch for controlling` the closing ot' said switch.

l0. n combination, a controller arranged to connect a motor armature to different sets ot multiple. voltage mains, a resistance, a switch arranged to be operated to cnt said resistance into the motor armature circuit when the' armature connections are changed troni one set ot' multiple voltage mains to another, a latch for holding said switch in the position in which the resistance is in the motorarmature, and electro-magnetically operated means for rendering said latch inoperative at'ter a time interval after the switch has been moved Vto cut the resistance in the motor armature circuit.

l1. In combination, a controller arranged to connect a motor armature to diilerent sets ot' multiple voltage mains, aV resistance` a 'switch arranged to be operated to cnt said resistance into the motor armature circziit when the armature connections are changed from one set ol multiple voltage mains to another, a latch for holding said switch in the position in which theresistance is in 'the motor armature, and electro-magnetic means for rendering,r` said latch inoperative alter a time interval after the switch has been moved to cut the resistance in the motor mature circuit, said elcctro-inagnctic means beingr energized upon the movement of the switch to ont said resistance into the motor armature circuit.

l2. in combination, a controller arranger to connect a motor arma ture to dillerent sets oi multiple voltage mains, a resistance tor the motor armature circuit, a Switch ncrmally short-circuiting,r said resistance, means for opening said switch by the movement of the controller to change the motor armature connections from one of multiple voltage mains to another, a latch it'or holding` faid switch open, and electro-magneticallyoperated means which operates after a time interval to render said latch inoperative.

123. ln combination, a controller arranged to connect a motor armature to dili'crent sets of multiple voltage mains, a resistance for the motor armature circuit, a Switch noi mally short-circniting said resistance, nieans for opening' said switch by the movement of the controller to change the motor armature connect ions from one set of multiple. voltage mains to another, a latch for holding said switch open, and electro-imxcnctic means which operates after a time interval to ren der said latch inoperative, said electro-magnetic means being' rendered operative by the opening' ot said switch.

ll. ln combination, a controllo arranged to connect a motor armature to different sets or' multiple voltage mains, a resistance for the motor armature circuit, an electro-.inagncl'ic coil, a switch normally short-circniting said resistance and said coil, means for opening said switch by the movement of the controllcr lo change the motor armature connec- 

